Homogeneous copper lead metal and method of making



C. E. BAZLEY HOMOGENEOUS COPPER LEAD METAL AND METHOD OF MAKING Filed Nov. 24, 1967 COPPER 2 Sheets-Sheet 1 MOLTEN COPPER LEAD MIXTURE MOLTEN MIXTURE LEAD AND COPPER CATALYST HOMOGENEOUS MIXTURE OF LEAD AND COPPER MOLD FIG.

' INVENT ORf CARL E. BAZLEY A TTORNE Y5 C. E. BAZLEY Dec. 1, 1970 HOMOGENEOUS COPPER LEAD METAL AND METHOD OF MAKING Filed Nov. 24, 1967 2 Sheets-Sheet 2 INVENTOR. CARL E. BAZLEY ATTORNEYS States Patent Oflice Patented Dec. 1, 1970 3,544,314 HOMOGENEOUS COPPER LEAD METAL AND METHOD OF MAKING Carl E. Bazley, Colorado Springs, Colo., assignor to Colea Metals International, Ltd., Denver, Colo., a corporation of Colorado Filed Nov. 24, 1967, Ser. No. 685,389 Int. Cl. C22c 9/08 US. Cl. 75-163 8 Claims ABSTRACT OF THE DISCLOSURE A. method of producing an intimate two phase solid mixture of copper and lead. The metal has a very low coefiicient of friction and is particularly suitable for bearings and other applications requiring low friction; it is effective as a high and low temperature seal as in water and steam packings and as a sliding contact or electric brush and it is useful in ballistic applications where low friction is essential. The method comprises melting copper and heating it to a predetermined temperature then adding the lead and reheating to the same temperature. A catalyst is then added and the melt poured into a mold and allowed to cool. The metal is remeltable repeatedly without the addition of catalyst or other additives.

This invention relates to a new metal consisting of a homogeneous solid mixture of copper and lead and to a method for making such metal.

It has been commonly accepted that copper and lead are not miscible to form a homogeneous solid mixture and such mixture is not found in nature. It has been known since about 1934 that these metals when heated together in equal proportions to a temperature over about 2800 F. are in a homogeneous state; however, the metals separate when cooled. Because of the individual properties of these metals it has been considered desirable to provide them in the form of a homogeneous solid mixture.

It is an object of the present invention to produce a homogeneous solid mixture of copper and lead.

It is another object of this invention to provide a process for making a homogeneous solid mixture of copper and lead.

It is another object of this invention to produce a metal consisting of a solid homogenous mixture of copper and lead and which may be melted and resolidified without loss of its homogeneous characteristic.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification.

Briefly, in carrying out the objects of this invention, a mass of copper is first melted and then raised to a temperature of about 2300 F. A quantity of lead not greater than that of the copper is then added to provide a mixture of the desired proportions of each metal. The melt is then raised again to a temperature of about 2300 F. a catalyst is then added to the high temperature melt whereupon the melt is poured into a mold or molds for cooling. The product of this process is a metal consisting of a homogeneous mixture of copper and lead which has a melting point about 100 F. lower than the melting point of copper.

For a better understanding of the invention, reference may be had to the following description taken into connection with the accompanying drawings in which:

FIG. 1 is a flow sheet illustrating the method of this invention;

FIG. 2 is a photomicrograph of the product of the invention containing 80% copper and 20% lead;

FIG. 3 is a photomicrograph of the product of the invention containing copper and 30% lead; and

FIG. 4 is a photomicrograph of the product of the invention having 60% copper and 40% lead.

Referring now to the drawing, the steps of the method of this invention are illustrated generally in the flow diagram FIG. 1. The various steps of the method are performed ina clean crucible which is first heated to a temperature of about 2300 F. copper from a source 10 is added to the crucible and is melted therein to provide molten copper as indicated at 11. The molten copper is heated to about 2300 F. and then a desired amount of lead is supplied from a source 12 and added to the mixture as indicated at 13. This molten mixture then is again reheated to a temperature of 2300 F. and provides the mixture at this temperature as indicated at 14. While maintaining the temperature of about 2300 F. a catalyst from a source 15 is added to the molten mixture which thereupon becomes a homogeneous mixture of lead and copper in the proportions determined by the quantity of each metal which have been employed. This homogeneous molten mixture is represented at 16. Directly after the addition of the catalyst the mixture is poured into a suitable mold indicated at 17 and is allowed to cool.

The catalyst 15 which is added to the molten mixture to secure the homogeneous mixture thereof may, for example, comprise equal portions of mineral salts from the group including torbernite and turquoise and of salts from the group including halite and glauberite. The minerals in the first group include copper phosphate and those in the second group sodium chloride or sodium sulphate. The catalyst is added in a proportion which lies in the range of one percent to four percent by weight of the weight of the molten mixture of copper and lead. After the catalyst has been added to the molten mixture it is not necessary to employ agitation, vibration, poling or any artificial stimulant to the molten mixture. The molten mixture is poured into the mold while the temperature remains above 2100 F. Sand cast well ventilated molds are used and it has been found that the structural qualities of the metal are improved by a long period of cooling. A useful product, however, may be obtained by using cold molds and instant cooling. When adding the catalyst it preferably is first enclosed in a lead capsule or sheath and is added to the molten mixture in this form. It has been found that impurities added to the molten mixture with the catalyst are not present in the final metal product but apparently are separated with the portion of the mixture which collects at the top of the mold and may readily be removed as by cutting off the sprue. Impurities may be avoided entirely by employing synthetic compounds of the required elements, and, for example, a pure copper phosphate and a pure sodium carbonate may be employed instead of the minerals identified above. The amount of the catalyst added may be varied depending upon the quality of the product desired, but in general it will lie in the range of one percent to four percent by weight of the molten mixture. It will thus be seen that the catalyst comprises essentially compounds of copper, phosphorus and sodium the proportions of each depending upon the minerals or other substances which are used; in general, the weight of sodium compound is of the order of the combined weights of the copper and phosphorus compound.

When employing the above identified synthetic compounds it has been found that for 50 pounds of the molten mixture the addition of 14 grams of a compound from each of the above groups providing a catalyst weight of 28 grams or one ounce results in the production of a metal having characteristics which are indicated generally in the four photomicrographs FIGS. 2, 3 and 4. In these figures, the white or light colored particles are the copper and the dark or black bodies in between are the lead. These photographs were made with a magnification of 75 to 1. The metal product of this process appears to be primarily a suspension of lead crystals in a copper matrix and it also appears that there is very little lead in solution in the copper and very little copper in solution in the lead. By scaling the photomicrograph FIG. 2, for example, the larger inclusions of lead may be estimated to have a minor dimension of about .002 to .004 inch. In the preparation of the samples represented by the photomicrographs FIGS. 2, 3 and 4, the individual samples were first electropolished and then etched using a phosphoric acid ethanol solution. Data obtained by X-ray defraction showed no new phases of the metals, only the lines of lead and copper appearing. There were no traces of other components such, for example, as those which might have been added with the catalyst.

The metal which is the product of the foregoing process melts at approximately 100 F. below the melting point of copper. When raised to this melting temperature the lead does not bleed or leach from the metal and it has been found that the metal may be melted and reheated many times without changing its structure. The metal is easily machined and formed, cold molded or sand cast and can be coined or extruded. The metal can be remelted and atomized into a fine powder without destroying its structural qualities. This metal in powder form can be sprayed by suitable spraying equipment using oxyacetylene heat. The material is self fluxed needs no additives and can be sprayed on any kind of steel, brass, bronze, copper andaluminum surfaces.

The physical characteristics of the metal produced by this invention make it highly desirable for applications where low friction is required. The metal has a very low coeflicicnt of friction and may be employed for bearings and for applications where sliding contact is required. It is particularly useful in electrical equipment where it may be employed as a brush or a sliding contact. .It is useful in gas seals and rotating hands, it is useful in ballistic applications, and, by way of example, a bullet having a coating of the metal has been found to have greatly increased penetrating ability. The metal may be powdered and sprayed onto other materials and can also be used as an additive to greases and oils for replacement of bearing surfaces or the coating of cylinder walls. The metal has high thermal conductivity and can be used for heat dissipating fins or other heat conducting elements. It is useful as a seal operating at high or low temperatures, and, for example, is useful for seals or packing in water and steam systems. The metal of this invention has excellent radiation absorption properties and is useful in gamma ray shielding. The metal may be used as a mother metal to blend with other metals, for example, with aluminum.

The metal of this invention may be reduced to a fine powder and it has been found that when reduced to a powder of about 325 mesh screen size the powder when not compacted acts as an electric insulator.

While this invention has been described in connection with specific proportions of materials and applications other modifications of the method and application of the metal will occur to those skilled in the art. Therefore, it is not desired that the invention be limited to the details illustrated and described and it is intended by the appended claims to cover all modifications of the method and materials which fall within the true spirit and scope of the invention.

I claim:

1. The method of producing a copper-lead metal constituting a two phase solid mixture of copper and lead with the lead uniformly distributed in the copper which comprises melting a quantity of copper, raising the temperature of the melt to about 2300 F., adding a quantity of lead not greater by weight than that of the copper, reheating the melt to about 2300 F., adding a catalyst having a weight of the order of from one to four percent of the weight of the melt, said catalyst comprising substantially equal parts of a mineralcomprising essentially a compound of copper and phosphorus and of a mineral comprising essentially a sodium salt, and directly thereafter pouring the melt into a mold.

2. The method of claim 1 wherein said catalyst is encllosed in a lead capsule before being added to the me t.

3. The method of claim 1 wherein said copper and phosphorus compound is contained in a mineral of the group consisting of torbernite and turquoise and said sodium salt is contained in a mineral of the group consisting of halite and glauberite.

4. A metal consisting of a two-phase solid mixture of copper and lead, the lead being uniformly distributed throughout the copper and said solid mixture being characterized by solidification without change in the uniformity of distribution of the lead after repeated meltings of the mixture.

5. The metal of claim 4 wherein said mixture comprises solely copper and lead and said copper and lead are pure metals.

6. The metal of claim 4 wherein said copper constitutes a matrix and said metal is characterized by a very low coefiicient of friction.

7. The metal of claim 4 characterized by a melting point approximately 100 F. lower than that of copper.

8. The method of producing a metal capable of repeated melting and resolidification and constituting a two phase solid mixture of copper with lead uniformly distributed therein, which comprises melting a quantity of copper, raising the temperature of the melt to about 2300 F., adding a quantity of lead not greater by weight than that of the copper, reheating the melt to about 2300 F., adding a catalyst having .a proportionate weight of the order of one ounce for each 50 pounds of the mixture, said catalyst comprising substantiallyequal parts of copper phosphate and of a salt selected from the group consisting of sodium chloride, sodium sulphate and sodium carbonate, and directly thereafter pouring the melt into a mold.

References Cited UNITED STATES PATENTS 1,024,561 4/1912 Davoren -163 X 1,234,547 7/1917 Kelly 75-163 1,664,708 4/ 1926 Schupp 75-163 1,910,446 5/1933 Pike 75-163 2,004,708 6/1935 Pfanstiehl 75-163 X 2,096,252 10/ 1937 Kochring 75-163 X 2,744,008 5/1956 Hammeras et al. 75-163 X OTHER REFERENCES Max Hansen: The Constitution of Binary Alloys, 2d ed., New York, McGraw-Hill, 1958, pp. 609-612 relied on.

L. DEWAYNE RUTLEDGE, Primary Examiner E. L. WEISE, Assistant Examiner U.S. Cl. X.R. 75-135 

